34th Annual Meeting of the Japanese Society for Neuroimmunology (JSNI)

The proceedings contain 14 papers. The topics discussed include: MOG-positive anti-NMDA receptor encephalitis with no demyelinating lesions: two case reports;safety and tolerability of rozanolixizumab in the randomized phase 3 MycarinG study;Outcomes from RAISE: A randomized, phase 3 trial of zilucoplan in generalized myasthenia gravis;efficacy and safety of zilucoplan in myasthenia gravis: responder analysis from the randomized Phase 3 RAISE trial;distinct effects among calcium-binding proteins for microglia to produce chemokines associated with the clinical severity of ALS;astroglial connexin 43 is a novel therapeutic target for a chronic multiple sclerosis model;targeting lymphocytes in SPMS: Th cell populations as a biomarker to predict the efficacy of Siponimod;CSF lysophospholipids as a novel biomarker in relapsing-remitting multiple sclerosis;the immune response to SARS-COV-2 MRNA vaccines in siponimod-treated patients with secondary progressive multiple sclerosis;patient characteristics of siponimod-treated SPMS patients in Japan: interim results from post-marketing surveillance;and efficacy of ravulizumab across sex and age subgroups of patients with generalized myasthenia gravis: a post hoc analysis of the CHAMPION MG study.

Regulatory role of endoplasmic reticulum resident chaperone protein ERp29 in anti-murine ß-coronavirus host cell response.

Gap junctional intercellular communication (GJIC) involving astrocytes is important for proper CNS homeostasis. As determined in our previous studies, trafficking of the predominant astrocyte GJ protein, Connexin43 (Cx43), is disrupted in response to infection with a neurotropic murine ß-coronavirus (MHV-A59). However, how host factors are involved in Cx43 trafficking and the infection response is not clear. Here, we show that Cx43 retention due to MHV-A59 infection was associated with increased ER stress and reduced expression of chaperone protein ERp29. Treatment of MHV-A59-infected astrocytes with the chemical chaperone 4-sodium phenylbutyrate increased ERp29 expression, rescued Cx43 transport to the cell surface, increased GJIC, and reduced ER stress. We obtained similar results using an astrocytoma cell line (delayed brain tumor) upon MHV-A59 infection. Critically, delayed brain tumor cells transfected to express exogenous ERp29 were less susceptible to MHV-A59 infection and showed increased Cx43-mediated GJIC. Treatment with Cx43 mimetic peptides inhibited GJIC and increased viral susceptibility, demonstrating a role for intercellular communication in reducing MHV-A59 infectivity. Taken together, these results support a therapeutically targetable ERp29-dependent mechanism where ß-coronavirus infectivity is modulated by reducing ER stress and rescuing Cx43 trafficking and function.

Protein Kinase C-Mediated Hyperphosphorylation and Lateralization of Connexin 43 Are Involved in Autoimmune Myocarditis-Induced Prolongation of QRS Complex.

Myocarditis is a serious and potentially life-threatening disease, which leads to cardiac dysfunction and sudden cardiac death. An increasing number of evidence suggests that myocarditis is also a malignant complication of coronavirus pneumonia, associated with heart failure and sudden cardiac death. Prolonged QRS complexes that are related to malignant arrhythmias caused by myocarditis significantly increase the risk of sudden cardiac death in patients. However, the molecular mechanisms are not fully known at present. In this study, we identify protein kinase C (PKC) as a new regulator of the QRS complex. In isolated hearts of normal rats, the PKC agonist, phorbol-12-myristate-13-acetate (PMA), induced prolongation of the QRS complex. Mechanistically, hyperphosphorylation and lateralization of connexin 43 (Cx43) by PKC induced depolymerization and internalization of Cx43 gap junction channels and prolongation of the QRS duration. Conversely, administration of the PKC inhibitor, Ro-32-0432, in experimental autoimmune myocarditis (EAM) rats after the most severe inflammation period still significantly rescued the stability of the Cx43 gap junction and alleviated prolongation of the QRS complex. Ro-32-0432 reduced phosphorylation and blocked translocation of Cx43 in EAM rat heart but did not regulate the mRNA expression level of ventricular ion channels and the other regulatory proteins, which indicates that the inhibition of PKC might have no protective effect on ion channels that generate ventricular action potential in EAM rats. These results suggest that the pharmacological inhibition of PKC ameliorates the prolongation of the QRS complex via suppression of Cx43 hyperphosphorylation, lateralization, and depolymerization of Cx43 gap junction channels in EAM rats, which provides a potential therapeutic strategy for myocarditis-induced arrhythmias.

Arrhythmogenic Cardiomyopathy: Exercise Pitfalls, Role of Connexin-43, and Moving beyond Antiarrhythmics.

Arrhythmogenic Cardiomyopathy (ACM), a Mendelian disorder that can affect both left and right ventricles, is most often associated with pathogenic desmosomal variants that can lead to fibrofatty replacement of the myocardium, a pathological hallmark of this disease. Current therapies are aimed to prevent the worsening of disease phenotypes and sudden cardiac death (SCD). Despite the use of implantable cardioverter defibrillators (ICDs) there is no present therapy that would mitigate the loss in electrical signal and propagation by these fibrofatty barriers. Recent studies have shown the influence of forced vs. voluntary exercise in a variety of healthy and diseased mice; more specifically, that exercised mice show increased Connexin-43 (Cx43) expression levels. Fascinatingly, increased Cx43 expression ameliorated the abnormal electrical signal conduction in the myocardium of diseased mice. These findings point to a major translational pitfall in current therapeutics for ACM patients, who are advised to completely cease exercising and already demonstrate reduced Cx43 levels at the myocyte intercalated disc. Considering cardiac dysfunction in ACM arises from the loss of cardiomyocytes and electrical signal conduction abnormalities, an increase in Cx43 expression-promoted by low to moderate intensity exercise and/or gene therapy-could very well improve cardiac function in ACM patients.

Mechanisms of SARS-CoV-2 and Male Infertility: Could Connexin and Pannexin Play a Role?

The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on male infertility has lately received significant attention. SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) in humans, has been shown to impose adverse effects on both the structural components and function of the testis, which potentially impact spermatogenesis. These adverse effects are partially explained by fever, systemic inflammation, oxidative stress, and an increased immune response leading to impaired blood-testis barrier. It has been well established that efficient cellular communication via gap junctions or functional channels is required for tissue homeostasis. Connexins and pannexins are two protein families that mediate autocrine and paracrine signaling between the cells and the extracellular environment. These channel-forming proteins have been shown to play a role in coordinating cellular communication in the testis and epididymis. Despite their role in maintaining a proper male reproductive milieu, their function is disrupted under pathological conditions. The involvement of these channels has been well documented in several physiological and pathological conditions and their designated function in infectious diseases. However, their role in COVID-19 and their meaningful contribution to male infertility remains to be elucidated. Therefore, this review highlights the multivariate pathophysiological mechanisms of SARS-CoV-2 involvement in male reproduction. It also aims to shed light on the role of connexin and pannexin channels in disease progression, emphasizing their unexplored role and regulation of SARS-CoV-2 pathophysiology. Finally, we hypothesize the possible involvement of connexins and pannexins in SARS-CoV-2 inducing male infertility to assist future research ideas targeting therapeutic approaches.

Effects of Drugs Formerly Proposed for COVID-19 Treatment on Connexin43 Hemichannels.

Connexin43 (Cx43) hemichannels form a pathway for cellular communication between the cell and its extracellular environment. Under pathological conditions, Cx43 hemichannels release adenosine triphosphate (ATP), which triggers inflammation. Over the past two years, azithromycin, chloroquine, dexamethasone, favipiravir, hydroxychloroquine, lopinavir, remdesivir, ribavirin, and ritonavir have been proposed as drugs for the treatment of the coronavirus disease 2019 (COVID-19), which is associated with prominent systemic inflammation. The current study aimed to investigate if Cx43 hemichannels, being key players in inflammation, could be affected by these drugs which were formerly designated as COVID-19 drugs. For this purpose, Cx43-transduced cells were exposed to these drugs. The effects on Cx43 hemichannel activity were assessed by measuring extracellular ATP release, while the effects at the transcriptional and translational levels were monitored by means of real-time quantitative reverse transcriptase polymerase chain reaction analysis and immunoblot analysis, respectively. Exposure to lopinavir and ritonavir combined (4:1 ratio), as well as to remdesivir, reduced Cx43 mRNA levels. None of the tested drugs affected Cx43 protein expression.

eP520: Screening results in 186 any-health-status adults in primary care clinics receiving clinical NGS for 431 health risk and recessive genes

Introduction: The ACMG has recommended returning clinically relevant results for certain genes when identified in research or as secondary findings in diagnostic testing. Research studies have shown that genomic population screening detects patients with previously unrecognized and often actionable health risks or genetic conditions, with acceptably low levels of harm. Cascade testing of relatives at risk is enabled. Screening for recessive disorder carrier status with gene sequencing panels is common in clinical practice. Preventative screenings routinely occur in primary care settings. The cost of reliably sequencing of many genes in a clinically reliable fashion is approaching levels where offering genomic screening tests may be contemplated for entire populations, and the results used for preventative health purposes, including clinical correlation, early screening, and education. In anticipation of universal genome sequence-based screening, integrated with existing health risk screenings, we piloted a novel implementation of clinical genomic population screening in primary care, mostly family medicine clinics. Screening involved clinical sequencing and reporting of 431 genes where variants are associated with personal health risks or recessive disease carrier status. Methods: Interested primary care providers (PCPs) in two Family Medicine practice systems were invited to participate and given onboarding education. Adult patients with any health status were introduced to The Genomic DNA Test and provided test information by their PCPs in the context of preventative health assessment. Patient education materials included paper, online, and video information, a ‘hotline,’ and optional free genetic counseling. Patients completing a bespoke, health system-approved, written clinical consent provided blood or occasionally saliva samples that were NGS sequenced according to validated procedures in a commercial CLIA-certified genetic testing laboratory. Laboratory reports were returned to the PCP and patient after a local genetics professional added a 1-to-3-page messaging document, the Genomic Medicine Action Plan (GMAP). The PDF-format reports and GMAP were placed in the patient’s electronic health record. Only pathogenic (P) and likely pathogenic (LP) variants were reported. Variant classification was according to Sherloc, the performing laboratory’s system. Patients or providers could request free post-test genetic counseling locally, and the performing lab offered free family member testing and limited-cost partner testing for health risk panel genes and recessive disorder panel genes, respectively. Patients with health risk results were defined as being heterozygous for a P/LP variant for a dominant condition or for a recessive condition where some heterozygotes are symptomatic or co-dominant, hemizygous for a P/LP variant for an X-linked recessive condition, or bi-allelic and plausibly in trans for an autosomal (or X-linked in a female) recessive condition. Many such conditions that are common have reduced or low penetrance, and were characterized as increased risk compared to those not having those variants. When increased risk was identified, the GMAP recommended appropriate medical responses and/or patient education. As part of quality assessment of the pilot, the frequencies of reported results and certain events are monitored. Results: Between November 2019 and October 2021, 186 patients with a median age of 58 years were tested by 20 PCPs at no cost to patients or insurance. Testing volumes declined during the COVID-19 pandemic and when other health system events made high demands on PCPs and their staff. Only 13.3% of patients had no reportable variants in any of the 431 genes. Eighty point nine percent were carriers for at least one recessive disease. The most common recessive genes showing carrier status were HFE, SERPINA1, GALT, CFTR, BTD, F5, DHCR7, PC, GAA, GJB2, PMM2, PAH, and PKHD1. Twenty-six percent had at least one potential health risk result identified, 20% if the common thrombophilias are excluded. The most common category was hereditary cancer risk (7.5%), followed by F5, F2, and SERPINC1 thrombophilia variants (6.5%), hereditary hemochromatosis 1 (HFE) (4.3%), cardiovascular disorders, mostly cardiomyopathies (3.8%), alpha-1-antitrypsin deficiency or other pulmonary disorder (3.8%), familial Mediterranean fever heterozygotes (1.6%), G6PD deficiency (1.1%), and lipid disorder (0.5%). Two patients had health risks in two areas, and two in three areas. Interestingly, BRCA1 and BRCA2 variants were only identified in males. Thirteen patients, about 7%, had an amended report issued during the period. This happened when an unreported variant of uncertain significance was reclassified as LP or P, or when LP became P, and the performing laboratory issued an amended report. Surprisingly few patients took advantage of the free genetic counseling. No patient adverse events were reported by the participating PCPs despite ongoing outreach, nor by patients. Conclusion: Genomic population health screening can be successfully implemented in primary care settings with use of limited but essential genetic professional assistance, after careful planning and input from other medical specialties. A significant proportion of adults not selected for health status harbors germline genetic variants associated with increased health risk. In the absence of a culture where routine genomic screening is expected and where patient genomic competency is high, PCP capacity limits are a barrier to universality. Inclusion of genes for both health risk results with variable degrees of penetrance and for recessive carrier status, and multiple simultaneous results, dictates careful messaging of the implications, while doing so in a primary care setting begs a concise and efficient process. Rates of carrier detection were in-line with predictions based on general population frequencies. Rates of health risk detections were higher than earlier research programs because a larger number of genes with a much broader scope of health risk was included, including disorders with low penetrance yet meaningful clinical relevance and carefully-designed care pathways meant to optimize care while avoiding unnecessary additional testing. We conclude that genomic population health screening of primary care patients where large numbers of genes are clinically sequenced is feasible in a real-world health system, and that value exists for some tested patients now. Research to overcome certain technical limitations of current clinical genomic testing methods and to better stratify risk level in the context of incomplete penetrance should enhance the value of universally-offered genomic population health screening in the future.

Unravelling Atrioventricular Block Risk in Inflammatory Diseases: Systemic Inflammation Acutely Delays Atrioventricular Conduction via a Cytokine-Mediated Inhibition of Connexin43 Expression.

Background Recent data suggest that systemic inflammation can negatively affect atrioventricular conduction, regardless of acute cardiac injury. Indeed, gap-junctions containing connexin43 coupling cardiomyocytes and inflammation-related cells (macrophages) are increasingly recognized as important factors regulating the conduction in the atrioventricular node. The aim of this study was to evaluate the acute impact of systemic inflammatory activation on atrioventricular conduction, and elucidate underlying mechanisms. Methods and Results We analyzed: (1) the PR-interval in patients with inflammatory diseases of different origins during active phase and recovery, and its association with inflammatory markers; (2) the existing correlation between connexin43 expression in the cardiac tissue and peripheral blood mononuclear cells (PBMC), and the changes occurring in patients with inflammatory diseases over time; (3) the acute effects of interleukin(IL)-6 on atrioventricular conduction in an in vivo animal model, and on connexin43 expression in vitro. In patients with elevated C-reactive protein levels, atrioventricular conduction indices are increased, but promptly normalized in association with inflammatory markers reduction, particularly IL-6. In these subjects, connexin43 expression in PBMC, which is correlative of that measured in the cardiac tissue, inversely associated with IL-6 changes. Moreover, direct IL-6 administration increased atrioventricular conduction indices in vivo in a guinea pig model, and IL-6 incubation in both cardiomyocytes and macrophages in culture, significantly reduced connexin43 proteins expression. Conclusions The data evidence that systemic inflammation can acutely worsen atrioventricular conduction, and that IL-6-induced down-regulation of cardiac connexin43 is a mechanistic pathway putatively involved in the process. Though reversible, these alterations could significantly increase the risk of severe atrioventricular blocks during active inflammatory processes.

Multi-organ damage by covid-19: congestive (cardio-pulmonary) heart failure, and blood-heart barrier leakage.

Corona virus disease-19 (covid-19) is caused by a coronavirus that is also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and is generally characterized by fever, respiratory inflammation, and multi-organ failure in susceptible hosts. One of the first things during inflammation is the response by acute phase proteins coupled with coagulation. The angiotensinogen (a substrate for hypertension) is one such acute phase protein and goes on to explain an association of covid-19 with that of angiotensin-converting enzyme-2 (ACE2, a metallopeptidase). Therefore, it is advisable to administer, and test the efficacy of specific blocker(s) of angiotensinogen such as siRNAs or antibodies to covid-19 subjects. Covid-19 activates neutrophils, macrophages, but decreases T-helper cells activity. The metalloproteinases promote the activation of these inflammatory immune cells, therefore; we surmise that doxycycline (a metalloproteinase inhibitor, and a safer antibiotic) would benefit the covid-19 subjects. Along these lines, an anti-acid has also been suggested for mitigation of the covid-19 complications. Interestingly, there are three primary vegetables (celery, carrot, and long-squash) which are alkaline in their pH-range as compared to many others. Hence, treatment with fresh juice (without any preservative) from these vegies or the antioxidants derived from purple carrot and cabbage together with appropriate anti-coagulants may also help prevent or lessen the detrimental effects of the covid-19 pathological outcomes. These suggested remedies might be included in the list of putative interventions that are currently being investigated towards mitigating the multi-organ damage by Covid-19 during the ongoing pandemic.